Highscore: kontextfreie Grammatiken

eindeutige Grammatik für {w : 2| w|_a = | w|_b}

Grammatik
    { terminale = mkSet "ab" 
    , variablen = mkSet "S" , start = 'S'
    , regeln = mkSet 
     [ ( "S" , "" ) 
     , ( "S" , "SaSbSb" ) 
     , ( "S" , "SbSbSa" )
     , ( "S" , "SbSaSb" ) ]
    }